1. Field of the Invention
The present invention relates generally to presses, and more particularly to, a method for intermittently punching material with a press.
2. Description of Related Art
Currently, presses are being used to remove or punch material when forming a part from a sheet of material. Typically, the press has a frame, an upper platen with a cutting or punching tool, a lower platen and means for moving the upper platen toward the lower platen. The frame for these presses is rather large in size and height to allow the upper platen to develop enough inertia for the cutting tool such that the cutting tool can stamp or punch the material in a single continuous stroke.
To cut or punch material in a single continuous stroke, the cutting force commonly needed is equal to the yield strength of the material times the length of the cut or punch. Typically, over thirty percent (30%) of the material thickness has to be exceeded in order to allow the material being cut or punched to separate from the remainder of the material. As a result, the frame of the press must be sufficient in size to provide the structural force needed to absorb the cutting pressure. This structural force commonly is equal to the mass of the cutting tool or punch times the inertia thereof.
One problem with conventional presses is that the frame of the press must be rather large in size and height to absorb the required cutting pressure. As a result, a corresponding room must be of large dimensions to contain the press. Another problem is that these presses commonly have a "pit" or cavity disposed below in the support surface to aid in containing the press. This requires the press to be placed in a predetermined position on the support surface. This limits the mobility of the press. A further problem is that heavy equipment is required to move the press. This also reduces the mobility of the press. A still further problem is that a large size and height of the press is required to develop the inertia necessary for punching or removing material in one continuous stroke.
It is, therefore, one object of the present invention to provide a method of removing or punching material that requires a press smaller in size and height than conventional presses.
It is another object of the present invention to reduce the inertia required for the punch or cutting tool.
It is a further object of the present invention to reduce the structural force required for the press when cutting or punching material.
This application is related to another application entitled "APPARATUS FOR PUNCHING MATERIAL" filed on the same date and having similar Specification and drawings.